<!DOCTYPE html>
<html lang="zh-cn">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
        <title>小图标与文字垂直居中对齐</title>
        <style>
            * {
              padding:0;
              margin:0;
              font-size:14px;
            }
            .close-btn {
              background:red;
              color:#fff;
              height:45px;
              line-height:45px;
              width:120px;
              border-radius:5px;
              text-align:center;
             }
             img {
                height: 14px;
                position: relative;
                top: 2px;
                left: 0;
             }
        </style>
    </head>
    <body>
        <div class="close-btn">
            <img src="http://s1.mi.com/m/images/20151028/top-x.png">
            <span class="text-close">
              关闭
            </span>
        </div>
    </body>
</html>